Pdsch in lte. 36. 8A and) HARQ Process for Downlink is similar to legacy LTE except that each transmission would happen in repetition in LTE-M1. to schedule Random Access Procedure initiated by a PDCCH Order; Followings are the summary of the DCI contents based on 36. Why don't we use PDCCH for ACK/NACK on network side. Power Control" and if you want to have some hands-on experience of these, I would recommand you to try some test items on 36. In this section, I will try to visualize several typical types of DCI operations as examples just to give you some big picture on how DCI works for PDSCH and PUSCH scheduling. CFI (Control Format Indicator) CFI is a indicator telling how many OFDM symbols are used for carrying control channel (e. At last, 3GPP Rel 11 adopted ePDCCH. com May 30, 2023 · PDSCH plays a crucial role in downlink data transmission in LTE and 5G wireless communication systems. It only shows the structure of one frame in time domain. There are commonality and differences in this process between legacy LTE and LTE-BL/CE. For PRACH Power, refer to "TS 36. 521 9. Apr 3, 2017 · Overview of Physical Downlink Control Channel (PDCCH) and Physical Downlink Shared Channel (PDSCH). The PBCH and PDDCH use the same kind of channel coding: a tail-biting k=7, r=1/3 convolutional code with a circular buffer for rate matching that performs puncturing and repetition coding as needed to obtain the 4G/LTE - PHY Processing PDCCH Resource Allocation . Jan 18, 2024 · In LTE (Long-Term Evolution), the PDSCH (Physical Downlink Shared Channel) is a fundamental component of the physical layer that is responsible for delivering user data to User Equipment (UE). Carries user specific data (DL Payload). 2_D - TDD CQI Reporting under fading conditions with PUSCH 3-1 for eDL MIMO . a) Network send DCI Format 0(UL Grant) without PDSCH transmission So blocking LTE CRS by NR PDSCH would lead to PDSCH decoding failure on LTE device. Introduction. The DCI bits have 16 bit CRC attached prior to rate-1/3 channel coding & rate matching modules. The PDSCH plays a crucial role in the downlink transmission, providing a shared channel for the delivery of user data, control information, and other Table-1 LTE PDCCH channel formats The PDCCH format is used as per required size of DCI. Downlink physical channels carry layer 2 information but downlink physical signals are only used by the physical layer. 1-1: Transport block size table as in legacy LTE. Code Rate . Condition : i) PDSCH via DCI Format 2C. RACH stands for R andom A ccess Ch annel. < Case 1 > < Case 2 > < Case 3 > < Case 4 > Physical Channel Structure. Good topic for you to think over -:) PHICH is carried by the first symbol of each subframe. and in WCDMA case it used special Apr 19, 2024 · This post is a continuation of my series about LTE, where I decode a recording of the downlink signal of an eNB using Jupyter notebooks written from scratch. PDSCH (Physical Downlink Shared Channel): PDSCH is a physical channel in the LTE downlink that is dedicated to delivering shared data to UEs. 211 for FDD LTE is as follows. In case of Asynchronous HARQ (e. g, QPSK, 16 QAM, 64 QAM, 256 QAM). This would seem to be very simple two step process, but to make this happen UE is capable of doing step ii), iii), iv) described above. You may know that MCS (Modulation Coding Scheme) is related to Modulation Order (Modulation Depth, e. 2-2 in 3GPP TS 36. This is the only downlink transport channel available to carry user data between the mobile device and the eNB. initiated by a PDCCH order As in legacy LTE, LTE-BL/CE UE also start with RACH process to get the initial access to a network. How many CCEs are necessary to carry one PDCCH ? In LTE the PDSCH carries the DL-SCH (Downlink Shared Channel). The PDCH is also used to transmit broadcast information not transmitted on the PBCH which include System Information Blocks May 15, 2024 · The Physical Downlink Shared Channel (PDSCH) is a crucial component in both LTE (Long-Term Evolution) and 5G wireless communication systems. 212 V13. As the name stands for, this is a reference signal for PUSCH implying that eNodeB would not be able to decode PUSCH if this PUSCH DMRS is bad. " In this video, we'll discuss downlink data transmission in 5G New Radio. See full list on mathworks. Format 6-1A . DCI format 6-1A is used for the compact scheduling of one PDSCH codeword in one cell and random access procedure. 4G/LTE - Basic Procedures PDCCH (Physical Downlink Control Channel) PDCCH is a physical In terms of Channel Process, PDSCH goes through following steps. DMRS - PUSCH . You don't have to try to understand the details of how this is generated (If you Three types of precoding are available in LTE for the PDSCH: spatial multiplexing, transmit diversity, and single antenna port transmission. 1. In other words, it means "The code rate is defined as the ratio between the transport block size and the total number of physical layer bits per subframe tha LTE RACH in Details . Why PDSCH DMRS ? In LTE, there is always on downlink reference siganal called CRS (Cell Reference Signal), but we This site is for everything on 4G/LTE. It seems that 3GPP adopted the (a) Pure FDM (Refere to 36. This is the first message from UE to eNB when you power it on. 4A/6. Simply put, the code rate can be defined as the ratio of the data rate that is allocated for a subframe and the maximum data rate that ideally can be allocated in the subframe. Downlink TBS Determination . 2-2: OFDM symbol indices within a slot where the ratio of the corresponding PDSCH EPRE to the cell-specific RS EPRE is denoted by r A or r B * Oct 16, 2023 · PDCCH and PDSCH configured by SI-RNTI (Table 7. The latter is used to map around LTE CRS in case NR and LTE share the same carrier. g, CQI 8) ii) UE sends a CQI report with a certain value (e. 3. iii) UE --> NW : HARQ ACK/NACK. DMRS stands for 'DeModulation Reference Signal'. transport block) processing through 5G NR physical layer modules or blocks. Correspondingly, the mapping of EPDCCH is based on enhanced control channel element (ECCE) and enhanced resource elements group (EREG) . The PDSCH channel is the main data bearing channel which is allocated to users on a dynamic and opportunistic basis. This page describes LTE PDSCH channel or Physical Downlink Shared Channel with respect to LTE system. Let us understand PDSCH channel data (i. 4G/LTE - Power Allocation. ii) UE <-- NW : PDSCH in repetition. For example, Reference Signal, PDCCH, PDSCH etc. Table 5. The highest level view from 36. For a long time since I joined into the wireless communication, this kind of processing has always the part that I was so eager to undersand but eventually gave up. e. g, PDSCH transmission in LTE), the sender should inform the receiver of HARQ processor number explictely. Introduction to PDSCH and PDCCH: 1. Note : Step i) and ii) happens not in the same subframe. 521. In case of LTE, DCI 1 and 2 carries this information as you see in the DCI 1 and DCI 2 examples. This is generated by Matlab LTE Toolbox and Refer to Matlab :ToolBox : LTE : Downlink : Cell Specific Reference Signal for the detailed Matlab source. Uplink case they just used PUCCH for carrying ACK/NACK for each PDSCH it recieved. . It plays a pivotal role in ensuring efficient and reliable communication in LTE networks. < LTE Downlink Refence Signal - Sequence Generation > One example of reference signal symbol data is as follows. Oct 22, 2017 · Thank you for sharing this insightful article on LTE throughput optimization and the role of PDCCH enhancements in achieving it. In case of LTE, all the possibility of RBS are precalculated and listed as a big table. LTE Physical Layer Overview. Here I will decode the PDSCH (physical downlink shared channel), which contains the data transmitted by the eNB to the UEs, including PDUs from the MAC layer, and some broadcast information, such as the SIB (system information block) and Jul 1, 2022 · The PDDCH contains control information, such as uplink grants and the scheduling of the PDSCH (physical downlink shared channel). Type 1 uses Frequency Division Duplexing (uplink and downlink separated by frequency), and TDD Time Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the Jan 18, 2024 · Let’s delve into the details of PDSCH and PDCCH, their functions, and their significance in LTE networks. 2) we can go back to your Gold Code circuit diagram and create the same diagram with 31 [D] cells (each [D] cell stores a single bit) and making our feedback wiring based on based on the above generator polynomials (see Channel Coding Processing for DL SCH/PCH/MCH. (It is located in the same symbol as PCFICH). The scrambling initialization of PDSCH corresponding to these PDCCHs is by SI-RNTI. If CFI is set to be 1 for a subframe, it means one symbol (the first symbol) at the subframe is May 23, 2019 · This is a new episode in our series, "5G Explained. 12 a) Network send PDCCH and PDSCH data. Overview - FDD : Frame Structure Type 1. In LTE, usually they use multiple Antenna for downlink (at least from Category 3 UE and higher), meaning that eNode (Network) has use multiple Tx Antenna and UE use multiple Rx antenna. Moreover, EPDCCH is mapped to PDSCH region. g, PDCCH and PHICH) at each subframe. It assumes that Initialization, Synchronization, IB decoding, Registration is already done and UE is in connected mode. Carries Random Access Response Message in case of PDSCH mapped to RACH channel. This site is for everything on 4G/LTE. For uplink resource allocation, refer to the post: PUSCH Resource Allocation in Frequency-Domain. 213 which is shown below. This process happens on UE's PHY Decoding process. 212 - 5. Once we know these, along with the fact that in 3GPP LTE the two m-sequences are 31 bits wide (as specified in chapter 7. PDSCH (LTE) PDSCH Physical Downlink Shared Channel is the Physical Downlink Shared Channel. 211 6. It introduces numerous changes and potential improvements for physical layer data transmissions, although only point-to-point (PTP) communications are considered. 1-1) If the UE is configured to decode PDCCH with CRC scrambled by the SI-RNTI, it decodes the PDCCH and the corresponding PDSCH according to any of the combinations defined in Table 7. The LTE Toolbox™ provides functions for physical layer modeling with varying levels of granularity ranging from system level functions that can generate the full uplink and downlink waveforms to PHY channel level functions that perform the transport/physical channel processing and individual channel processing stage functions performing CRC coding, turbo coding, etc. OK, now let's modify the previous scenario a little bit further as below. The difference between M1 and legacy LTE lies in mapping between I_MCS and I_TBS and the possible range of I_MCS. 213. Apr 5, 2020 · The post, Bandwidth Parts thoroughly discusses about BWP allocation and this post discusses PDSCH resource allocation in frequency domain in detail. It implies this cannot be used when PDSCH start symbol is greater than 3. Feb 5, 2024 · This article "LTE Throughput Optimization: Part 2 - Spectral Efficiency" explains data part (PDSCH) of the LTE subframe and discusses various ways to improve its efficiency. One PHICH is carried by multiple REG. However, in NR the TBS determination process is described as a sequence of algorithm as summarized below (I think it will take a while to get familiar with this When receiving unicast PDSCH, UE can be informed that certain resources are not available for PDSCH. Dec 30, 2023 · Mapping and Transmission: Once modulated and coded, the PDSCH symbols are mapped to the allocated resources within the LTE frame structure. 1-1 of 3GPP TS 36. This mapping ensures that the UE knows where to look within the frame to decode the PDSCH data intended for it. There are two types of frame structure in the LTE Long Term Evolution standard, Type 1 and Type 2. The rough HARQ sequence would be as follows. i) eNB sends a PDSCH with the condition for a certain CQI (e. This MATLAB function performs the inverse of physical downlink shared channel (PDSCH) processing on the matrix of complex modulated PDSCH symbols, sym, using cell-wide settings structure, enb, and channel-specific configuration structure, chs. The spectral efficiency is simply the number of bits transmitted over a frequency bandwidth in a specific time and is measured in bits/s/Hz. It provides efficient and reliable delivery of user data by utilizing resource allocation, channel coding, modulation, HARQ, beamforming, MIMO, and interference management techniques. We will look at the downlink shared channel chain, which includes LDPC coding, the physical downlink shared channel chain, our resource elements are allocated for PDSCH transmission, the different types of PDSCH mapping, and conclude with a quick word on transport block However, determining TBS (Transport block size) in NR is more complicated than the one in LTE. 0 (2016-06) - 5. 211 36. This procedure will explain the overall procedure to decode user data (PDSCH). Each ECCE comprises of 4 EREG's 5 , and each EREG consists on 9 RE's 6 in one PRB pair. Now we have special types of LTE specially designed for IoT/M2M application and DCI operation has been changed even further. When RB Auto Detect is selected and RB Auto Detect Mode is set to Power Based, the demodulator groups resource blocks by modulation type and shows three groups (PDSCH_QPSK, PDSCH_QAM16, and PDSCH_QAM64) on the Frame Summary trace. 7. What are same ? What are the differences ? SIB Parameters for RACH; RACH Sequence for Initial Access; Step (A) : SIB2; Step (B) : Msg1 (Preamble) Transmission Important thing to notice is that ePDCCH is allocated in those symbols allocated for PDSCH for conventional LTE. Step 2 : DCI format 0 reception. MCS and Modulation Order . Even though they use a little bit different name, in all cellular technology (CDMA, GSM, WCDMA, LTE) there is a specific signal that perform the same function. 1 Physical non-synchronized random access procedure". The following list describes LTE downlink physical channels and physical signals. For details of LTE specific power control, you have to refer to "TS 36. This is used for following purpose : to schedule PDSCH. One PDCCH is carried by multiple number of consecutive CCEs. The PDSCH (LTE-Advanced) Menu Path: Trace > Data > CCx > Demod > Frame Summary where x specifies the component carrier PDSCH is the Physical Downlink Shared Channel. If you look into the downlink signal, you would notice that it is made up of many different components. How does a mobile know where there is data for it in the LTE-BL/CE (LTE-M1) - MCS/TBS Determination . So LTE introduces a couple of resource allocation types and each of the resource allocation type uses a predefined procedures. This modulation order is defined as a Parameter called Qm in 3GPP and the relationship between MCS value and Qm is defined in a little bit differently for PDSCH and PUSCH in the three tables Most important parameters related to Resource Allocation in Time Domain and Ack/Nack responses are : k0, k1, k2, SLIV, N1, N2; k0 indicates the number of time slot between PDCCH/DCI and Downlink Data(PDSCH) transmission (e. TBS (Transport Block Size) for BL/CE UE is determined by 36. If you enjoy using our glossary, here are some other useful resources you might like DCI format 1A is used for the compact scheduling of one PDSCH codeword in one cell and random access procedure initiated by a PDCCH order . Oct 5, 2023 · The Physical Downlink Shared Channel (PDSCH) is a fundamental component of LTE (Long-Term Evolution) communication that plays a critical role in delivering data to user equipment (UE), such as smartphones and tablets. Let’s delve into its technical details: Purpose: The primary purpose of the PDSCH is to deliver downlink user data and higher-layer signaling to the user equipment (UE). The example aids understanding of the control region used in an LTE downlink subframe and its channel structure by showing how a downlink control information (DCI) message is generated and transmitted over a physical downlink control channel (PDCCH) and recovered by performing blind decoding using the LTE Toolbox™. 12 says. p-C-r10 0 // the assumed ratio of PDSCH EPRE to CSI-RS EPRE // when UE derives CSI feedback }+ }} Example 9 : 36. In case When the UE is scheduled to receive PDSCH by a DCI, the Time domain resource assignment field of the DCI provides a row index of a higher layer configured table pdsch-symbolAllocation, where the indexed row defines the slot offset K0, the start and length indicator SLIV, and the PDSCH mapping type to be assumed in the PDSCH reception. 2. The breakdown of PDCCH structure and its aggregation layers provided a clear understanding of how scheduling allocations work for PDSCH and PUSCH, making it easier to comprehend the overall optimization process. If you are adding a new PDSCH, when you click OK, the PDSCH channel is added to the bottom of the list of sym = ltePDSCH(enb,chs,cws) returns a matrix containing the physical downlink shared channel (PDSCH) complex symbols for cell-wide settings, enb, channel transmission configuration, chs, and the codeword or codewords contained in cws. ii) Physical channel for CQI/PMI reporting : PUSCH The PDSCH/C-RS power ratio for the PDSCH subcarriers in each symbol is determined by Table 5. Transmission Mode . g, CQI 6) iii) (if it is live network, eNB would send PDSCH with MCS corresponding to CQI 6, but) eNB sends PDSCH with the same CQI (same MCS) regardless of the CQI value from UE. This is the downlink data channel for users. If you select an existing PDSCH channel and click the Physical Channel Configuration button, the Configure PDSCH window opens in which you can specify the modulation type, frame number, subframe number, and resource blocks for the PDSCH. i) UE <-- NW : MPDCCH (DCI for PDCCH) in repetition. PDSCH is a physical channel that carries user data. Within spatial multiplexing, there are two schemes: precoding with large delay cyclic delay diversity (CDD), also known as open loop spatial multiplexing, and precoding without CDD, also known as closed Getting more specifically into LTE, this RNTI is used to indentify one specific radio channel from other radio channel and one user from another user. As you may recall, in WCDMA is a RNTI concept which is carried as part of MAC header to deferentiate one user to another while in communication state. 213 - 5. The PDSCH channel is used to carry DL user data, UE specific upper layer informations (layer-2 and above), system informations and paging. What about in case of Synchronous HARQ? You don't have to inform Process ID in this case since the process ID This site is for everything on 4G/LTE. b) See if UE properly decode PDSCH data. There are three different resource allocation types in LTE, Resource Allocation Type 0, 1, 2. 5G New Radio (NR) Release 15 has been specified in June 2018. These unavailable resources may include configurable rate matching patterns with RB and symbol level granularity or RE level granularity. What is this for ? It is a special physical signal for downlink radio channel estimation especially for decoding PDSCH. 213 Table 7. g, if DCI and PDSCH is in the same slot, k0 becomes 0) Let us understand PDSCH channel processing using 5G NR physical layer modules. 1. How about this ? In this scenario, NR PDSCH is punctured (rate matches) around NR CRS and LTE CRS now visible to the mobile device across the full frequency span. Sep 11, 2023 · What is physical downlink shared channel in LTE? In Long-Term Evolution (LTE), the Physical Downlink Shared Channel (PDSCH) is a critical component of the radio interface responsible for delivering user data and control information to user devices (UEs). Power Control in LTE . First as a disclaimer, I am very early stage of studying this field. In order to use physical data channels such as the Physical Downlink Shared Channel (PDSCH), it is essential to guarantee a successful transmission of control information PDSCH DMRS is Type A; The DMRS location is fixed to 3rd (pos2) or 4th(pos3) PDSCH Starting Symbol can be 0~3; PDSCH Length can be 3~14 in case of normal CP and 3~12 in case of extended CP; the DMRS symbol can start only at symbol 2 or 3 regardless of PDSCH start and length. 213 - 6. Decoding at UE: The UE receives the PDSCH along with other signals like PTRS (if present). techs uwpvkv hagfx bwe ollhtg eekpcdz zpcacki ogsixai ygdlsy ascc